Characteristics Of Mycoherbicide Sclerotinia Sclerotiorum And Cloning, Expression Of The Corresponding Gene

Weed management is being developed into the comprehensive prevention along with the more understanding of chemical pesticide pollution. In the comprehensive prevention, bioherbicide and chemical hebicide are used together frequently. To study the effect of chemical herbicide on bioherbicide and resolve the bioherbicide assort with chemical herbicide is the basis of the weed comprehensive prevention. Sclerotinia sclerotiorum is a potential mycoherbicide. The interrelation between the fungus and chemical herbicides is not assayed. In this research, the effect of five herbicides on the growth of S. sclerotiorum, the characterization of EPSP synthase from the fungus, and the cloning and expression of the corresponding arom gene were studied in order to supply a gene, which could be used to construct the glyphosate-resistant bioherbicide, and provide the basis for resolving the problem of the consistence of bioherbicide and chemical herbicide to develop the comprehensive prevention.In the laboratory condition, the effects of atrazine, paraquat, Roundup?, 2.4-D butylate or bentazone at the different concentrations on S. sclerotiorum were assayed. The result showed that all the five herbicides did not inhibit or stimulate sclerotia germination. The growth rate of the fungus was not affected by atrazine, Roundup? or 2.4-D butylate at the field rate (P>0.05) while it was inhibited significantly by paraquat or bentazone at the field rate (P<0.01). The sclerotia growth was not influenced by Roundup? at the assayed concentrations, but it was by the other compounds to some content.AROM protein of S. sclerotiorum was partially purified by the method of ion-exchange chromatography and gel filtration, and then the effects of a series of factors on EPSP synthase activity were assayed. The results indicated that the pH optimum of the enzyme was 7.2. The temperature optimum was at 30℃. The stability scope against acid and alkali was pH6.7-7.2. The stability scope against heat was 30-40℃. Activation by K+ or EDTA as well as inhibition by some metal ions such as Fe 2+ , Mn 2+ , Cu 2+ , etc, urea and two substrates at the high concentrations was observed in the forward reaction. The kinetic pattern of the enzyme was consistent with a sequential mechanism. Inhibition of the enzyme...